Damage? No, probably not. That being said, if you interrupt the stream and then you don't quite get everything out, you might be at a higher risk for a UTI. When you get older (and especially if you have prostate issues), losing that initial flow could be enough to keep a little bit of urine backed up in the urethra, which is where that UTI risk comes in. Assuming you don't just ooze a bunch of piss down the front of your pants